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Tuesday, August 20, 2013

Rounding the downwind mark

Here's one that's fresh from the racetrack. Two boats on port tack approaching the downwind mark. The first boat gybes to starboard (2) right at the edge of the zone. This kinda opens up the overlap zone. Both boats carry on and at the mark (3) Yellow yells "no room" and tries to close the gap. Blue seeks the space between the mark and yellow but fails to execute the turn and slams (4) right into yellow. Yellow protests!

Fresh from the race track

What did the jury say? What should yellow have done? What should blue have done?

PS: That Boat Scenario program is supereasy to use. If only those animated files could be made smaller.

Yellow entered the zone first and clear ahead. Blue is not entitled to any room. in addition, yellow is on starboard tack so she is not required to make a seaman like rounding; i.e. she can go wide and come in close to clear the mark. Blue must stay clear.

If I was in Yellow's shoes I'd closed the door on Blue already earlier; not to fight Blue or force them to make an error but just to not waste that much height on the upcoming upwinds leg. Bad course planning by both yachts, who lost oversight because they only cared about their insignificant boat to boat fight.

I was mistaken. Blue does have the slight overlap at position 2 and is entitled to room. Tillerman is also right that Blue should be exonerated under 14b if no damage occurred. However, on watching the scenario closely and discovering my mistake, it appears that Blue made a less than seamanlike rounding which might lead to only Blue being DSQ.

The drawning is pretty accurate. Blue got an overlap at the zone, only because yellow gybed 3 seconds too early. So tactically, Tillerman is right. That t-bone at position 4 did indeed cause hull damage. Blue could have avoided the collision quite easily by swinging to port. She didn't so she is out.